(1) Field of the Invention
The present invention relates to an apparatus for detecting a vehicle-in-blind-spot and, in particular, to an apparatus for detecting the vehicle via sounds.
(2) Description of the Related Art
Information on blind spots is vital for a vehicle operator in order to drive safely. For safe driving, proposed have been various techniques to provide information on the blind spots to assist safe driving of the operator (See Patent Reference 1: Japanese Unexamined Patent Application Publication No. 2007-233770, Patent Reference 2: Japanese Unexamined Patent Application Publication No. 2007-323556, Patent Reference 3: Japanese Unexamined Patent Application Publication No. 2007-233864, and Patent Reference 4: Japanese Unexamined Patent Application Publication No. 2004-102579).
Patent Reference 1 proposes a technique to: determine a blind spot area out of (i) map information and (ii) a detection result, of an obstacle, obtained by radar; and present the operator the information on the determined blind spot area.
Patent Reference 2 proposes a technique to employ a communications apparatus to detect an approaching vehicle-in-blind-spot, and to give an alarm to the operator on the approaching vehicle.
Moreover, Patent Reference 3 proposes a technique to provide prioritized pieces of information on a blind spot according to a degree of hazard determined based on information obtained via communications between a roadside device and another vehicle. This technique reduces driving distractions and disturbances caused in providing the information.
In addition, Patent Reference 4, which is not designed for detecting a vehicle-in-blind-spot, proposes a technique to employ a sound to detect an approaching vehicle, and to gives an alarm to the operator on the approaching vehicle.
The technique proposed in Patent Reference 1 can detect the blind spot per se; however, the technique fails to provide the fact whether or not there is a vehicle in the blind spot area.
The techniques proposed in Patent References 2 and 3 require the other vehicle, as well as the operator's vehicle, to have the communications apparatus used for detecting the vehicle-in-blind-spot. The resulting problem is that the vehicle in the blind spot cannot be detected in the case where only the operator's vehicle is equipped with the apparatus for detecting the blind spot (the communications apparatus).
Furthermore, the technique proposed in Patent Reference 4 detects all of the approaching vehicles; however, the technique fails to determine whether or not the vehicles are in the blind spot. Accordingly, the technique gives alarms on all the approaching vehicles to the operator, which is disturbing to the operator.